KR20060079597A - Method for controlling pixels of liquid crystal display apparatus - Google Patents

Abstract

A pixel driving method of a liquid crystal display device capable of improving display characteristics is disclosed. When the image data corresponding to the image is input, the liquid crystal display displays the image while periodically changing the position of the sub-pixel turned off in the main pixel corresponding to the image. Accordingly, when the liquid crystal display displays a specific image for a long time, deterioration and afterimage can be prevented from occurring in a specific subpixel, and thus display characteristics can be improved.

Deterioration

Description

Pixel driving method of liquid crystal display device {METHOD FOR CONTROLLING PIXELS OF LIQUID CRYSTAL DISPLAY APPARATUS}

1 is a plan view illustrating a liquid crystal display according to an exemplary embodiment of the present invention.

2 is a flowchart illustrating a process of displaying an image in a liquid crystal display according to an exemplary embodiment of the present invention.

3 is a plan view illustrating an example in which an image is displayed in FIG. 2.

4 is a diagram illustrating an example of driving pixels in response to the image of FIG. 3.

FIG. 5 is a diagram illustrating another example of driving pixels in response to the image of FIG. 3.

6 is a flowchart illustrating a process of displaying an image in a liquid crystal display according to another exemplary embodiment of the present invention.

FIG. 7 is a diagram illustrating an example of driving pixels in response to an image in FIG. 6.

<Description of the symbols for the main parts of the drawings>

100 liquid crystal display device 110 thin film transistor substrate

120: color filter substrate 130: liquid crystal layer

140, 150, 160: main pixel

The present invention relates to a pixel driving method of a liquid crystal display device, and more particularly, to a pixel driving method of a liquid crystal display device capable of improving display characteristics.

In general, the liquid crystal display is a type of flat panel display and displays an image by using optical characteristics of the liquid crystal. The liquid crystal display includes a liquid crystal display panel displaying an image corresponding to image data input using light and a backlight assembly providing light to the liquid crystal display panel.

The liquid crystal display panel is composed of pixels, which are basic units for displaying an image, and one pixel of the RGB color pixels is positioned in each pixel. The liquid crystal display panel receives image data in units of dots, and dots are formed of three pixels adjacent to each other. The signal voltage corresponding to the image data is applied for each pixel.

In general, a sub screen, an electronic board, an instrument panel, etc. of a mobile phone mainly display a fixed image displaying only one image for a long time, for example, date information, time information, and battery level displayed on a sub screen of the mobile phone. Since a fixed image has little change in the screen and one image lasts for a long time, a specific pixel is turned on for a long time. As a result, deterioration occurs in the pixel and affects the refractive index of the liquid crystal. Therefore, it is difficult to express vivid colors, and afterimages occur.

SUMMARY OF THE INVENTION An object of the present invention is to provide a pixel driving method of a liquid crystal display device which can prevent display deterioration and improve display characteristics.

In a pixel driving method of a liquid crystal display according to an aspect for realizing the object of the present invention, first, a first pixel corresponding to an image is turned on during a driving time, and is located adjacent to the first pixel. The second pixel is turned off. When the driving time of the first pixel exceeds the preset driving time, the first pixel is turned off and the second pixel is turned on.

In addition, the pixel driving method of the liquid crystal display device according to an aspect for realizing the above object of the present invention, first, for each of the first to third sub-pixels having a first gray value corresponding to the image is provided in the main pixel; Is generated. The main pixel displays a first color corresponding to the first grayscale value during the driving time. The second grayscale value corresponding to the image is generated for each of the first to third subpixels by comparing whether the time in which the first color is displayed exceeds the preset driving time. The main pixel displays a second color corresponding to the second grayscale value during the preset driving time.

According to the pixel driving method of the liquid crystal display device, since the position of the sub-pixel turned off periodically changes while displaying the same image, it is possible to prevent deterioration from occurring in the specific sub-pixel.

Hereinafter, with reference to the accompanying drawings, it will be described in detail the present invention.

1 is a plan view illustrating a liquid crystal display according to an exemplary embodiment of the present invention.

Referring to FIG. 1, the liquid crystal display 100 according to the present invention displays an image corresponding to image data by using light provided from the outside. A TFT substrate 110 having a thin film transistor (hereinafter, referred to as TFT), a color filter substrate 120 that is coupled to the TFT substrate 110 to face each other, and a liquid crystal layer 300 that controls light transmittance Include.

In more detail, the TFT substrate 110 is formed in the form of a matrix of the TFTs acting as switching elements. The TFT applies and cuts a signal voltage corresponding to the image data to the liquid crystal layer 300. A pixel electrode for providing the signal voltage to the liquid crystal layer 300 is provided on the TFT, and the pixel electrode is made of a transparent conductive electrode.

The color filter substrate 120 provided on the TFT substrate 110 may apply a color filter layer expressing a predetermined color using light provided from the outside, and apply a common voltage to the liquid crystal layer 300. It includes a common electrode.

The color filter layer is formed in a thin film process and has RGB color pixels. The common electrode made of a transparent conductive electrode is provided on an upper surface of the color filter layer and faces the pixel electrode.

On the other hand, the liquid crystal layer 300 is interposed between the TFT substrate 100 and the color filter substrate 200. The liquid crystal layer 300 adjusts the transmittance of the light according to an electric field formed between the pixel electrode and the common electrode.

The display area DP in which the image is displayed in the liquid crystal display device 100 includes main pixels. The image data is applied to each main pixel 140, and the main pixel 140 includes three sub-pixels 141, 142, and 143. The TFT is formed in each of the sub-pixels 141, 142, and 143, and any one of the RGB color pixels is formed. The signal voltage corresponding to the image data is applied to each of the subpixels 141, 142, and 143.

2 is a flowchart illustrating a process of displaying an image in a liquid crystal display according to an exemplary embodiment of the present invention.

1 and 2, first, as the image data is input, a first subpixel of the first main pixel among the first and second main pixels corresponding to the image data among the main pixels; And the second and third subpixels of the second main pixel positioned adjacent to the first main pixel are turned on (step S110). Second and third subpixels of the first main pixel and the first subpixel of the second main pixel are turned off.

The time interval between the time when the first sub-pixel of the first main pixel 140 is turned on and the current time is compared with the preset driving time (step S120).

If the driving time of the first sub-pixel of the first main pixel 140 is smaller than the preset driving time in step S120, the current state is maintained (step S110).

When the driving time of the first subpixel of the first main pixel 140 exceeds the preset driving time in step S120, the first subpixel of the first main pixel is turned off. The second subpixel is turned on. In the second main pixel, the second subpixel is turned off and the first and third subpixels are turned on (step S130).

When the second subpixel of the first main pixel is turned on, it is compared whether the driving time of the second subpixel of the first main pixel exceeds the preset driving time (step S140).

If the driving time of the second sub-pixel of the first main pixel is less than the preset driving time in step S140, the current state is maintained (step S130).

When the driving time of the second subpixel of the first main pixel exceeds the preset driving time in step S140, the second subpixel of the first main pixel is turned off and the first main pixel is turned off. The third subpixel of is turned on. The third located subpixel of the second main pixel is turned off, and the first and second located subpixels are turned on (step S150).

The liquid crystal display device 100 repeats the above process until new image data is input.

As such, while the image is displayed, the subpixels of the first main pixel and the subpixels of the second main pixel are opposite to each other. The subpixels turned on periodically change in the first main pixel. The subpixel turned on in the first main pixel is turned on during the driving time. The second main pixel periodically turns off the subpixel. The sub-pixels turned off in the second main pixel remain turned off during the driving time.

Therefore, the time for keeping the subpixels of the first main pixel turned off is twice the time for keeping the subpixels of the second main pixel turned off.

As described above, the liquid crystal display 100 changes subpixels that are turned off among subpixels corresponding to the image. Accordingly, when the liquid crystal display 100 displays a specific image for a long time, the liquid crystal display device 100 may prevent the signal from being deteriorated due to a long application of a signal voltage to the specific pixel.

3 is a plan view illustrating an example in which an image is displayed in FIG. 2, and FIG. 4 is a diagram illustrating an example of driving pixels in response to the image shown in FIG. 3.

2 to 4, the liquid crystal display 100 may drive each of the sub-pixels as shown in FIG. 4 to display an image P of 'a' in the display area DP. Can be.

The main pixels corresponding to the image P include first to third main pixels 140, 150, and 160. The first main pixel 140 includes first to third subpixels 141, 142, and 144, and the first to third subpixels 141, 142, and 143 are in a first direction D1. Are arranged sequentially.

The second main pixel 150 is positioned adjacent to the first main pixel 140 in a second direction D2 that is substantially orthogonal to the first direction D1. The second main pixel 150 includes fourth to sixth subpixels 151, 152, and 153, and the fourth to sixth subpixels 151, 152, and 153 may face the first direction D1. Are arranged sequentially.

The third main pixel 160 is positioned adjacent to the second main pixel 150 in the second direction D2. The third main pixel 160 includes seventh to ninth subpixels 161, 162, and 163, and the seventh to ninth subpixels 161, 162, and 163 correspond to the first direction D1. Are arranged sequentially.

The first, fourth, and seventh sub-pixels 141, 151, and 161 are sequentially positioned in the second direction D2, and R color pixels are formed. The second, fifth, and eighth subpixels 142, 152, and 162 are sequentially positioned in the second direction D2, and a G color pixel is formed. The third, sixth, and ninth subpixels 143, 153, and 163 are sequentially positioned in the second direction D2, and a B pixel is formed.

When the image data corresponding to the image P is input, the liquid crystal display device 100 turns on the first subpixel 141 of the first main pixel 140 during the preset driving time. The second and third subpixels 142 and 143 are turned off. In the second main pixel 150, the fourth subpixel 151 is turned off and the fifth and sixth subpixels 152 and 153 are turned on during the driving time. In the third main pixel 160, the seventh subpixel 161 is turned on during the driving time, and the eighth and ninth subpixels 162 and 163 are turned off.

That is, in the first and third main pixels 140 and 160, the first subpixels 141 and 161 are turned on, and the second subpixels 142 and 162 and the third subpixels 142 and 162 are positioned. Subpixels 143 and 163 are turned off, respectively. In the second main pixel 150, the first and third main pixels 140 and 160 are first turned off, and the second and third subpixels 152 are turned off. 153 are each turned on.

Among the main pixels corresponding to the image, the main pixels positioned on the same line in the first direction D1 and in the first direction D1 are the same as the first main pixel 140. The pixel is turned on and the second and third subpixels are turned off. Similarly, among the main pixels corresponding to the image, the main pixels positioned on the same line in the first direction D1 as the third main pixel 160 are the same as the third main pixel 160 in the first position. Only subpixels that are turned on are turned on.

Among the main pixels corresponding to the image, the main pixels positioned on the same line in the first direction D1 as the second main pixel 150 are the same as the second main pixel 150. The pixel is turned off and the second and third subpixels are turned off.

This state is maintained for the preset driving time, and after the preset driving time, the first and third subpixels 141 and 143 of the first main pixel 140 are turned off and the second Subpixel 142 is turned on. In the second main pixel 150, the fourth and sixth subpixels 151 and 153 are turned on, and the fifth subpixel 152 is turned off. In the third main pixel 160, the first and third subpixels 161 and 163 are turned off, and the second subpixel 162 is turned on. This state is maintained for the second driving time.

As such, the first and third main pixels 140 and 160 have the same sub-pixels that are turned on and the sub-pixels that are turned off, and the first and third main pixels 140 and 160 are the same. The two main pixels 150 are turned on and different from the sub-pixels turned off.

That is, the two main pixels adjacent to each other in the second direction D2 have different turn-on subpixels and turn-off subpixels. For example, when the first subpixel 141 of the first main pixel 140 is turned on and the second and third subpixels 142 and 143 are turned off, the second main pixel 150 is turned on. Fourth subpixel 151 is turned on, and the fifth and sixth subpixels 152 and 153 are turned off.

As such, the liquid crystal display 100 may have different subpixels that are turned off and subpixels that are turned off between two main pixels adjacent to each other in the second direction D2 while the image P is displayed. The sub-pixels turned off periodically change.

Therefore, when the liquid crystal display device 100 displays a fixed image with little change in the input image data, the position of the sub-pixel turned off at each main pixel corresponding to the fixed image is changed periodically. As a result, the signal voltage is applied to a specific subpixel for a long time among the subpixels corresponding to the fixed image, thereby preventing deterioration of the subpixel.

FIG. 5 is a diagram illustrating another example of driving pixels in response to the image of FIG. 3.

The main pixels shown in FIG. 5 have the same structure as the main pixels shown in FIG. 4. In this embodiment, the main pixels denote the same reference numerals as those of the main pixels in FIG. 4, and a detailed description thereof is omitted.

Referring to FIGS. 3 and 5, when the image data corresponding to the image P is input, the liquid crystal display 100 receives the first of the first and third main pixels 140 and 160 during the driving time. The first subpixels 141 and 161 and the third subpixels 143 and 163 are turned on, respectively, and the second subpixels of the first and third main pixels 140 and 160 ( 142 and 162 are turned off, respectively. On the contrary, in the second main pixel 150, the second subpixel 152 is turned on, and the first and third subpixels 153 are turned off.

That is, the first and third subpixels 141 and 143 of the first main pixel 140 are turned on during the driving time, and the second subpixel 142 is turned off. In the second main pixel 150, the fourth and sixth subpixels 151 and 153 are turned off and the fifth subpixel 152 is turned on during the driving time. In the third main pixel 160, the seventh and ninth subpixels 161 and 163 are turned on during the first driving time, and the eighth subpixel 162 is turned off.

Among the subpixels corresponding to the image P, subpixels positioned on the same line in the second direction D are alternately housed with subpixels turned on and subpixels turned off.

If the driving time of the first and third sub-pixels 141 and 143 of the first main pixel 140 exceeds the preset driving time, the first and third main pixels Secondly located subpixels 142 and 152 of 140 and 160 are turned on, and firstly located subpixels 141 and 151 and third of the first and third main pixels 140 and 160 are turned on. The located subpixels 143 and 153 are turned off, respectively. On the contrary, in the second main pixel 150, the first and third subpixels 153 are turned off, and the second subpixel 152 is turned on.

That is, the first and third subpixels 141 and 143 of the first main pixel 140 are turned on during the driving time, and the second subpixel 142 is turned off. In the second main pixel 150, the fourth and sixth subpixels 151 and 153 are turned off and the fifth subpixel 152 is turned on during the driving time. In the third main pixel 160, the seventh and ninth subpixels 161 and 163 are turned on during the first driving time, and the eighth subpixel 162 is turned off.

Among the subpixels corresponding to the image P, the subpixels positioned on the same line in the second direction D are alternately positioned with the subpixels turned on and the subpixels turned off. In addition, the subpixels positioned on the same line in the second direction D periodically change between the subpixels turned on and the subpixels turned off.

That is, when the input image data displays a fixed image with little change, the liquid crystal display 100 periodically turns off sub-pixels of the main pixels corresponding to the fixed image. As a result, the signal voltage is applied to a specific subpixel for a long time among the subpixels corresponding to the fixed image, thereby preventing deterioration of the subpixel.

6 is a flowchart illustrating a process of displaying an image in a liquid crystal display according to another exemplary embodiment of the present invention.

1 and 6, in the process of displaying an image in the liquid crystal display according to the present invention, first, each sub-pixel of each main pixel corresponding to the image is input as the liquid crystal display device 100 receives image data. A first gray scale value is generated for each pixel (step S210). The first gray level values provided to the main pixels corresponding to the image are the same for each subpixel of each main pixel. That is, the gradation value applied to the first subpixel of the first main pixel and the gradation value applied to the first subpixel of the second main pixel are the same.

Each main pixel displays a first color corresponding to the first gray value for a preset driving time (step S220). Main pixels corresponding to the image display the same color.

It is compared whether the time when the first color is displayed exceeds a preset driving time (step S230).

If the time at which the first color is displayed in step S230 is smaller than the preset driving time, the current state is maintained (step S240).

When the time at which the first color is displayed in step S230 exceeds the preset driving time, a second gray level value is generated for each subpixel of each main pixel corresponding to the image (step S240). The first gray value and the second gray value are different from each other.

Each main pixel displays a second color corresponding to the second grayscale value for a preset driving time (step S250). The first color and the second color are different from each other, and the liquid crystal display device 100 repeats the above process until new image data is input.

As described above, the liquid crystal display 100 periodically changes colors corresponding to the same image. Accordingly, since the sub-pixels turned off in each main pixel are periodically changed, it is possible to prevent a phenomenon in which signal voltage is applied to a specific pixel for a long time and deterioration occurs.

FIG. 7 is a diagram illustrating an example of driving pixels in response to an image in FIG. 6.

7 is a diagram illustrating a method of displaying the image P illustrated in FIG. 3, wherein the main pixels illustrated in FIG. 7 have the same structure as the main pixels illustrated in FIG. 4. In this embodiment, the main pixels denote the same reference numerals as those of the main pixels in FIG. 4, and a detailed description thereof is omitted.

6 and 7, when the image data corresponding to the image P is input, the liquid crystal display device 100 (see FIG. 1) may include first to first values during the driving time according to the first gray value. The first subpixels 141, 151, and 161 of the third main pixels 140, 150, and 160 are turned on, respectively, and the second positions of the first to third main pixels 140, 150, and 160 are turned on. The subpixels 142, 152, and 162 and the third subpixels 143, 153, and 163 are turned off.

Since each main pixel corresponding to the image P is all turned on with the same subpixel, the image P is represented by a single color. Since the R pixel is formed in the first subpixels 141, 151, and 161 of the main pixels 140, 150, and 160, the image P has a current mode of Normal Black. If it is, the color is displayed in red, and in the normal white mode, it is displayed in yellow. Since the gray value corresponding to the image P varies with color, the first gray value varies with the current mode.

As described above, the color displaying the image P is different depending on the current mode. The second and third subpixels of the respective main pixels are to be displayed in the normal white mode and the red color as in the normal black mode. Should turn on. Therefore, since the time for one subpixel to be turned off is shorter than the normal black mode, it is displayed in a different color from the normal black mode for the same.

If the time in which the image P is displayed in red exceeds the driving time, the second sub-th of the first to third main pixels 140, 150, and 160 during the driving time according to the second gray value is included. The pixels 142, 152, and 162 are turned on, respectively, and the first subpixels 141, 151, 161 and the third subpixels of the first to third main pixels 140, 150, and 160 are respectively turned on. Pixels 143, 153, and 163 are turned off, respectively.

Since the G color is located in the second subpixels 142, 152, and 162 of the main pixels 140, 150, and 160, when the current mode is a normal black mode, the image P is green ( Green), and if the current mode is a normal white mode, the image P is represented by magenta.

When the time in which the image P is displayed in the color corresponding to the second gray scale value exceeds the preset driving time, the first to third main pixels 140, 150, and 160 during the preset driving time. The third located subpixels 143, 153, and 163 are turned on, respectively, and the first located subpixels 141, 151, and 161 of the first to third main pixels 140, 150, and 160 are respectively turned on. And the second located subpixels 142, 152, and 162 are turned off, respectively.

The B pixel is formed in the third subpixels 143, 153, and 163 of the main pixels 140, 150, and 160, so that when the current mode is the normal black mode, the image P is blue ( If the current mode is a normal white mode, the image P is represented by cyan.

As such, among the subpixels corresponding to the image P, the subpixels positioned on the same line in the second direction D are all turned on or turned off in the same manner. Each of the main pixels periodically turns on, and thus the color corresponding to the image P changes periodically.

Accordingly, the liquid crystal display 100 may prevent deterioration of the subpixel by applying the signal voltage to a specific subpixel for a long time when displaying the fixed image with almost no change in the input image data. .

According to the present invention described above, the liquid crystal display device periodically changes the position of the sub-pixel turned off from the main pixel while displaying the same image. Accordingly, when a fixed screen displaying the same image for a long time is displayed, the liquid crystal display prevents the signal voltage from being applied only to a specific subpixel, thereby preventing deterioration of the subpixel. As a result, the liquid crystal display can prevent the refractive index of liquid crystals sensitive to temperature from changing due to deterioration of the subpixels, and can prevent the afterimage from remaining, thereby improving display characteristics.

Although described above with reference to the embodiments, those skilled in the art can be variously modified and changed within the scope of the invention without departing from the spirit and scope of the invention described in the claims below. I can understand.

Claims (9)

In the pixel driving method of a liquid crystal display device having a first pixel and a second pixel which are located adjacent to each other, the same image data is applied, Turning on the first pixel for a preset driving time and turning off the second pixel; And And turning off the first pixel and turning on the second pixel by comparing whether the driving time of the turned on first pixel exceeds the preset driving time. Pixel driving method. The method of claim 1, wherein the turning on the second pixel comprises: Comparing the driving time of the first pixel with the predetermined driving time; If the driving time of the first pixel exceeds the predetermined driving time, turning off the first pixel and turning on the second pixel; And And turning on the first pixel when the driving time of the first pixel is smaller than the predetermined driving time. The pixel of claim 1, wherein the first and second pixels are formed of any one of RGB color pixels, and the first and second pixels are formed of the same color pixel. Driving method. In the pixel driving method of a liquid crystal display device comprising a main pixel consisting of first to third sub-pixels for displaying the same image, Generating a first gray value corresponding to the image for each of the first to third subpixels; Displaying, by the main pixel, a first color corresponding to the first gray value during a preset driving time; Comparing the time when the first color is displayed with the predetermined driving time to generate a second gray value corresponding to the image for each of the first to third sub-pixels; And And the main pixel comprises displaying a second color corresponding to the second gray level value during the preset driving time. The method of claim 4, wherein the generating of the second gray level value comprises: Comparing whether the time at which the first color is displayed exceeds the preset driving time; Generating the second gray scale value when the time at which the first color is displayed exceeds the preset driving time; And And if the time when the first color is displayed is smaller than the preset driving time, the main pixel includes maintaining the currently displayed color. The method of claim 4, wherein displaying the first or second color comprises turning on only one subpixel of the first to third subpixels to display the first or second color. A pixel driving method of a liquid crystal display device. The pixel of claim 6, wherein the first and second colors are any one of yellow, cyan, and magenta in a normal white mode. Driving method. 7. The pixel of claim 6, wherein the first and second colors are any one of blue, green, and red in a normal black mode. Driving method. 5. The liquid crystal of claim 4, wherein the first to third subpixels are formed of any one of RGB color pixels, and the first to third subpixels are formed of different color pixels. 6. A pixel driving method of a display device.

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